Method of reacting castor oil and an organic polyisocyanate in the presence of an organometallic tin catalyst



United States Patent METHOD 6F REACTlNG CASTOR OlL AND AN ORGANICPOLYISOCYANATE IN THE PRES- ENCE OF- AN GRGANGMETALLIC TEN CATA- LYS lFritz Hostettler and Eugene. E. Cox, both of Charleston, W- V3-,.!SSigfiES. to. Union Carbide. Co p a a a on o N w York No Drawing. Originalapplication Sept. 25, 1957, Scr. Nc.686,0'31'.Dividedandtliisapplication June 23, 1961,5ar1No. 119,024"

2 @laims. (fill; 269-4945);

Thisinvention relates. to methods for accelerating reactions of organiccompounds having reactive groups of the, formula NCY,. in which Y isoxygen or sulfur, with compounds having groups, containing reactivehydrogen as determined by the Zerewitinoffmethod: de scribed in LAm...Chem. Soc.., vol. 49, page/3181 (1927). These methods. are generically.usefulin promoting reactions of isocyanates. and isothiocyanates with awide variety of active hydrogen-containing compounds and have foundparticular and immediate applicability in'the preparation ofpolyurethanes, a broad class of organic polymers formed. by reactions.of dior polyisocyanates or dior polyisothiocyanates.with a large varietyof difunctional or polyfunctional compounds having hydroxylor aminogroups containing active hydrogen, e.g., water, polyols, polyamines,polyethers, polyesters, polyoxy-carbooxy alkylenes, and the like.

A very considerable number. of materials have heretofore beenproposedascatalysts for accelerating isocyanate reactions generally. andpolyurethane preparationin particular. One, of the most. importantdisadvantages that is common to all but, a few of, the catalysts knownto have been proposed is that. they do not accelerate the reactionsufiiciently to bring it within the realm of practical utility. Tertiaryamines, the most popular catalysts known to have been proposedheretofore, provide slow reaction rates unless used in unsatisfactorilylarge amounts, typical formulations requiring one to three parts byweight of amine per 100 parts of total composition. Another veryimportant disadvantage of proposed catalysts, including tertiary amines,is that they requireelevated temperatures in reactions involvingaromatic isocyanates and are essentially inactive in promoting reactionsof aliphatic isocyanates at any reasonable temperature. Tertiary aminesoften impart an undesirable odor to reaction products of isocyanateswith active hydrogen-containing compounds and, due to their basiccharacteristics, catalyze the degradation of the reaction products orpolymers once they are formed. Cobalt naphthenate, another popularcatalyst, has the disadvantage of imparting undesired-color totheraction product and of requiring: a petroleum: base solvent whichleads to the formation of tacky foams of relatively high density. strongbases such as sodium hydroxide, whi'chpi'ovide greater acceleration,frequently lead to uncontrollable reactions, particularly in formingpolyurethane foams, and bring about excess cross linkingQ Ferricacetylacetonate, a compoundcon sidered to be non-organometallic becauseof the absence of any carbon to metal bond, is active but has thedisadvantages of being colored andof beingcatalytically active inoxidative degradation of organic compounds.

Other disadvantages of heretofore proposed catalysts includediscoloration, particularly yellowing'on aging of the reaction products,poor control over the progress of the reaction and a tendency to requireuse of high temperatures to bring about a satisfactory rate of reaction;

We have found that organotin compounds character'- ized by the presencetherein of-"at least one direct carbon to tin bond are ideally suitedfor acceleratingreactions of organic compounds having one or morereactive NCY groups in which Y is oxygen or sulfur with compounds havinggroups. containing activehydrogen. Reaction rates that are obtainable inaccordance with the method of the invention are up to many thousandtimes the-rates achieved with the best catalysts heretofore proposed.These tin catalysts furthermore are essentially colorless; can be usedin extremely small concentrations; have no tendency to degrade a polymerafter it is formed; generally introduce no. troublesome, odor problems;permit reactions at practicable and controllable rates without, in mostinstances, requiring heating of the reactants; and broaden the fi'eld ofuseful isocy anates for polyurethane forma tion toin'clude suchrelatively non-reactive materials as aliphatic. isccyanates andisothiocyanates.

Extensivetesting of a largevariety of organotin; compounds has indicatedthat while they vary somewhat intlieir activity, all tin'compoundshaving adirect carbon totin bond possess outstanding catalytic activity,as demonstrated in test results later described The tin compounds ofmost intense, ye't' controllableand therefore optimum catalyticactivity, are those having from one to. three carbon bonds directly) toa given tin ator'nand one 'or-m ore'catalytically intensifying bondsfrom said given tinatom to'a halogen, hydrogen, oxygen, sulfur, nitrogenor phosphorus atom. Among the many types of tin compounds having carbonto tin bonds, of'which specific representative compounds have beentested and shown to be active, are:

(A) Tin compounds having four carbon to tin bonds and nointensifyingbonds. such as tetramethyltin, tetra.- ethyltin,tetrapropylti'n; tetrabutyltin, tetraoctyltin, tetralauryltin,tetrabenzyltin, tetrakis(2-phenylethyl)tin, tetraphenyltin,tetraparatolyltin, tetravinyltin, tetraallyltin, tetrachloromethyltin,tetramethylsulfonylmethyltin, tetrap'ara-m'ethoxyplienyltin, tetrarparanitrophenyltin, as well as unsymmetrical compounds as exemplified by2-cyan o ethyltributyltin, dibutyldiphenyltin and various additionproducts 'o'fallfcyl, aryl' and'aralkyltin hydrides with unsaturatedorganic compounds'sucli as acrylonitrile, allyl cyanide, crotonitrile,acrylamide, methyl acrylate, allyl alcohol, acroleindiethyl acetal,vinyl acetate, styrene, etc.

(B) Tin compounds having n carbon to tin bonds and 4 -n intensifyingbonds from tin to halogen or hydrogen atoms or hydroxyl groups in whichI; is an integer from 1 to 3, such astrirnethyltin chloride,tributyltin' chloride, trioctyltin chloride, triphenyltin chloride,trimethyltin bromide, tributyltin fluoride, triallyltinchloridmtributyltin hydride, tripheiiyltin hydride,"trimethyltinhydroxide, tributyltin hydroxide, dimethyltin dichloride, dibut yltindichloride, dioctyltin dichloride, bis(2-phenylethyl)tin dichloride,diphenyltin dichloride,,divinyltin dichloride, diallyl-tin dibromide,diallyltin diiodide, dibutyltin difluoride, his(carboethoxymethyl)tindiiodide, bis(1,3-diketopentaneltin dichloride, dibutyltin dihydride,butyltin trichloride. I and octyltin trichloride.

'(C) Tin compounds having two carbon to tin bonds and a catalyticallyintensifying double bond from tin to oxygen. of sulfur, such asdirnethyltin oxide, diethyltin oxide, dibutyltin oxide, dioctyltinoxide, dilaur-yltin oxide, diplienyltin oxide and diallyltin oxide, allprepared by hydrolysis of. the corresponding dihalides, as, well as his2-'pheriylethyltin oxide, [HOOC(CH 1 8110 [C iz O '2( .H2O H2)x i H2Q(2)5]2S butyltin sulfide, the a s being whole integers.

(D) Tin compounds having a C'rllbOIllO tin bonds and 4-11 intensifyingbonds from tin to oxygen, sulfur, nitrogenfor phosphorus linking organicradicals, n" being an integer from 1 to 3, such as tributyltin'methoxide, tri- 3 butyltin bntoxide, tribntyltin acetate, tributyltinN-piperazinylthiocarbonylmercaptide, tribntyltin phosphorus dibutoxide[prepared as indicated immediately below:

WCJIQOMP P013 swnnonroi (G flflasncl as (C Em snNa NaGl NH: (C H9)3S11Na(osHaohPcl olnatsnrwoimn NaCl] dibntyltin dibutoxide,

C l-I Sn OCH CH O CH CH CH 2 dibutyl bis(O-acetylacetonyl)tin,dibutyltin bis(octyl maleate), Advastab T50LT -(a dibutyltin compoundfound, upon analysis, to contain two ester groups), Advastab 17M (adibutyltin compound found, upon analysis, to contain twosulfur-containing ester groups), Argus Mark A, Thermolite 20 [twotrade-names for dibutyltin bis(thiododecoxide)], dibutyltin -bis(octylthioglycolate), dibutyltin bis(N-morpholinylcarbonylmethylmercaptide),'dibutyltin dibenzenesulfonamide, dimethyltin diacetate, diethyltindiacetate, dibutyltin diacetate, diocty-ltin diacetate, dilauryltindiacetate, dibutyltin dilaurate, dibutyltin maleate, dibutyltinbis(N-piperazinylthiocarbonylmercaptide, dioctyltinbis(N-piperazinylthiocarbonylmercaptide), octyltin .tris(thiobntoxide),butyltin triacetate, methylstannonic acid, ethylstannonic acid,butylstannonic acid, octylstannonic acid,

HOOC(CH SnOOH (CH N (CH SnOOH CI-I OCH (CH O CH CH SnO OH and X 1CH2Owhich the xs are positive integers.

(E) Polystannic compounds having carbon to tin bonds and preferably alsointensifying bonds from tin to halogen, hydrogen, oxygen, sulfur,nitrogen or phosphorus, such as HO0Sn(CI-I ),,SnOOH and HOOSnCI-I (CHOCI-I CH SnOOH the xs being positive integers, bis-trimethyltin,bis-triphenyltin, bis-tributyl distannoxane, dibntylin basic laurate,dibutyltin basic hexoxide and other polymeric phenyltin, bis-tributyldistannoxane, dibutyltin basic and preferably also intensifyingbonds,e.g., those having repeating groups, dimers and trimers of (R SnY), andthe like in which the Rs may be alkyl, aryl or aralkyl radicals and theYs are chalcogens, as well as many other organetin compounds proposed asheat and light stabilizers for chlorinated polymers and available undersuch tradenames as Advastab, Nuostabe, and Thermolite.

The ability of representative tin compounds characterized by a directcarbon to tin bond to accelerate isocyanate reactions is demonstrated byreacting phenyl isocyanate withmethanol under essentially identical andcontrolled conditions. This reaction is important in such processes asthe formation of polyurethanes by reaction of isocyanates withpolyethers or polyesters. These tests were carried out in each instanceby admixing equimolar amounts of phenyl isocyanate and methanol inn-butyl other as solvent, adding a diflierent catalyst to the mixture,and observing the rate of reaction at 30 C. The reaction, catalysts andrelative rates based on one mol percent of catalyst per mol ofisocyanate are shown immediately below:

( (G H9) 2 O G5H5NCO CH OH 0,;H5NHOOOCH;

Catalyst: Relative rate None 1 p-Toluenesnlfonic acid 2 Acetic acid 3N-methylmorpholine 3 Triethylamine 1 l Cobalt naphthenate 23 Sodiummethoxide Ferric chloride 180 Tetrabutyltin 80 Tetraoctyltin 50Tetrakis(2-phenylethyl)tin 490 Tetraphenyltin 9 2-Cyanoethyltributyltin50 Dibutyldiphenyltin 3S0 Tributyltin chloride 400 Triphenyltin chloride20 Tributyltin fluoride 88 Tributyltin hydride 80 Tn'methyltin hydroxide2400 Tribntyltin hydroxide 500 Dimethyltin dichloride 2000 Dibutyltindichloride 200 Dioctyltin dichloride 200 -Bis(2-phenylethyl)tindichloride 1800 Divinyltin dichloride Dibutyltin difluoride 67Dibutyltin dihydride 69 Butyltin trichloride 800 Octylt-in trich'loride500 Dimethyltin oxide 11,000 iDibut-yltin oxide 40,000 Dioctyltin oxide20,000 Dibutyltin sulfide 16 Tributyltin' butoxide 400 Tribntyltinacetate 500 Tributyltin phosphorous dibutoxide 1200 Dibntyltindibutoxi-de 40,000 (C,,H Sn[OCH (CH OCH CH- OCH 30,000 Dibutylbis(O-acetylacetonyD-tin 20,000 Dibuty-ltin bis(octyl maleate) 15,000Advastab 17 M 7000 Advastab T-67l 11,000 Advastab T50-LT 20,000 ArgusMark A 19,000 Dibutyltin bis(thiododecoxide) 25,000 Di-butyltindibenzenesulfonamide 18,000 Dimethyltin diacetate 16,000 Dibntyltindiacet'ate 30,000 Dioctyltin diacetate 20,000 Dibutyltin dilaurate40,000 iDibu-tyltin maleate 30,000 Butyltin triacetate 1400Bis-triphenyltin 26 Bis(-tributyltin) oxide [(C H Sn]- O 500 This dataindicates that tetraphenyltin, one of the least active of the organictin catalysts, is only slightly less active than triethylamine, thestrongest of several tertiary amines examined. Tributyltin actate, anexample of an organotin derivative of medium catalytic activity is aboutfifty times more active than triethylamine, while dioctyltin oxide, oneof the very active organ'o-tin compounds, is 2000 times more effectivethan triethylaminc. Cobalt naphthenate, which has been used in someisocyanate recations but has the disadvantage of discoloring thereaction product, is about twice as active as triethylamine. Sodiummethoxide is moderately active, consider-ably better than amines, but byno means approachring the activity of the better organo-tin compoundslisted and unsuitable because of premature gelling of the reactants.Significantly, trimethyltin hydroxide, a moderately strong base, is afar better catalyst than such common bases as sodium andbenzyltrimethylammonium hydroxides.

When the same reaction is carried out in dioxane as solvent, the resultsare:

(11') CJHSOZ CQH5NOO CHQOH CH5NHCOOOH3 Catalyst: Relative rate None 1Triethylamine 100 Tetra-p-nitrophenyltin 130 Triallyltin chloride 6800Diphenyltin dichloride 160 'Bis(carboethoxyme thyl) tin diiodide 5 800Dioctyltin oxide 50,000 Bis(2-phenylethyl) tin oxide 30,000 TributyltinN -piperazinylthiocarbonylmercaptide 150 Di-butyltin bis (octylthioglycolate) 1700 Dibut-yltinbis(N-morpholin-ylcarbonylmethylmerc-aptide) 1100 Dibutylt-in diacetate.200,000 Di-butyltin bis(N-piperazinylthiocarbonylmercaptide) 550Dioctyltin bis(N-pipenazinylthiocarbonylmereaptide) 180 This data showsthe catalytic activity of representative tin compounds to be equallyeffective when the reaction is' carried out in dioxane under otherwisesimilar conditions.

Another extremely important reaction is that of isocyanates with water.The products are carbon dioxide and isocyanate residues linked byur-ylene links, the carbon dioxide being the blowing or foaming agent inpolyurethane foam production and the urylene links serving to connectchains of isocyanate-moditied polyesters and the like. In the tablebelow are. listed the approximate relative rates of reaction of phenylisocyanate with water in dioxane as solvent at 30*" C. and in thepresence of 1.0 mol percent (based on isocyanate) of some of the typicalcatalysts used. The reaction, catalysts and relative rates were asfollows:

III) i soz QCfiHsNCO 1120 W OQH5NHCONHCGH5 CO:

Catalyst: Relative rate None 1.0 Acetic acid 1.1 Triethylamine t 19Dimethyltin dichloride 36 Dimethyltin diacetate 46 0 Dibutyltindiacetate 600 Dioctyltin oxide 380 This data again reveals the definiteadvantage of the new catalysts over conventional tertiary amines. Actualfoaming experience has shown that the quantity of organotin catalystrequired for a particular foaming experiment correlates well with therate data for the phenyl isocyanate-water reaction.

The new metal compounds are also very effective catalysts for thereaction of an isocyanate with a urea. This reaction is especiallyimportant in polyurethane chemistry because it is a principal crosslinking or curing reaction. The reaction of phenyl isocyanate withdiphenylurea in dioxane at 70 C., as well as the relative rates withrepresentative catalysts in concentrations of one mole percent based onisoc-yanate are indicated immediately below:

Iv 4 sO2 oamNQo C5H5NHQQNHC6H5 W o tfitNno one o HCBHE 5H5. Catalyst;Relative rate None 1 Triethylamine t 10 Dibut-ylti n diacetate 300 Theorganotin compounds that. are useful in accordance with they inventionare exceptionally good catalysts for reactions of aliphatic isocyanates.The following tables list the appropriate relative rates for reactionsof octadecyl isocyanate with methanol, 1-butanol and Water in n-butylether at 30 C. and in dioxane at 70 C. in the presence of representativecatalysts, again on the basis of 1.0 mol percent concentrations:

The catalytic efiiciency of organo-tin compounds in acceleratingreactions of aliphatic isocyanates with alcohols and Water is indeedstriking when compared to the ineffectiveness of triethylamine.

To further demonstrate the relative activity of tin catalysts inaccelerating reactions between an active hydrogen-containingcornpoundand primary, secondary and tertiary aliphatic isocyanates, three"isomeric octyl isocyana-tes, i.e., l-octyl'isocyanate, Z-methylheptylisocyanate and 1,l-dimethylheiqzlj isocyanate, were reactedwithequim-ol-ar amounts of normal-butyl alcohol. with no catalyst, andwith triethylamine and dibutyltin diacetate as catalysts. in dioxane at:70 C. The relative rates,

based on the presence of one mol percent, catalyst, are

shown in the following table;

Catalyst Isoeyanate None Triethyl- Dibutyltin amine diacetate'11C7H15CH2NC O 1.0 1'. 7 11, 000

11-O H 3-OHNC O 0. 45 0.80 6, 500

CH3 nC5H JNC O 027 13 650 The data in this table indicates again thesuperior activity of organotin compounds, as represented by dibu-tyl-tindiacetate as a catalyst for the reaction and the relative inefficiencyof triethylamine as a catalyst.

Isothiocyanates are considerably less reactive than isocyanates towardcompounds containing active hydrogen. Diisothiocyanates have beenproposed for use in preparing polyurethane coatings but, because oftheir low reactivity with difunctional active hydrogen-containingcompounds, have hitherto not shown much promise. The organo-tincompounds are excellent catalysts for such reactions. The data recordedbelow for reaction of phenyl isothiocyanate and l-butanol in thepresence of ten mol percent catalyst at 70 C. in butyl ether demonstrateclearly the extremely high activity of organs-tin catalysts.

(VIII) The catalytic activity of organo-tin compounds in acceleratingreactions of diisocyanates with compounds containing reactive hydrogenis demonstrated by comparing reaction rates of 2,4-tolylene-,hexamethyleneand metaxylylene diisocyanates with l-butanol without acatalyst and in the presence of 'triethylamine and dibutyltin diacetate.The first of these diisocyanates is well known as a reactant in thepreparation of polyurethanes and the latter two, although otherwisepromising, have not been considered useful heretofore because of the lowrate of activity even with the best of catalysts'heretofore proposed.The data recorded below for the reaction of these diisocyana-tes withl-butanol in the presence of one moi percent catalyst at 70 C. indioxane demonstrates the favorable accelerations obtained:

(IX) i 0411502 R(NOO)2 2CiHaOH W C4H9OOONHRNHCOOC4H0 CatalystDiisocyanate None Tricthyl- Dibutyltin amine diacetate 2,4-tolylene 1.3. 8 2, 040 Hexarnethylene 0. 33 0. 82 1, 400 Meta-xylylene 0. 33 7. 93, 700

It is surprising that the tin catalyst accelerates the reaction ofmeta-xylylene diisocyana-te even. more than of 2,4-tolylene diisocyanateinasmuch as the reaction rate of the meta-xylylene diisocyanate withouta catalyst is slower. It is also significant that the reaction rate ofhexamethylene diisocyanate with dibutyltin diacetate as a catalyst ismany times greater than the reaction rate of the tolylene diisocyanatewith triethylamine as a catalyst,

thus making feasible the use of hexamethylene diisocyof the scope of theinvention.

To further illustrate some of the more practical applivigorous stirrin 3cations of the catalytic method of this invention and demonstrate by wayof example the utility thereof in the formation of polyurethanes, thefollowing additional examples are included:

Example 1 228 grams of epsilon-caprolactone, 176 grams of ethylene oxideand 11.4 grams of ethylene glycol were copolymerized in the presence of0.55 gram of boron trifiuoride-diethyl etherate (47% BP to form linearlactone-ethylene oxide copolyrners having divalent ethylene andpentamethylene groups connected to one another by oxy (-O) and carbooxy(COO) links, a hydroxyl number of 50.5 and a carboxyl number of 2.0.

Twenty-gram portions of the lactone-ethylene oxide copolymer thusprepared were mixed at room temperature with 1.74 ml. of a 65:35 mixtureof 2,4- and 2,6- toiylene diisocyanate in the presence of 0.1 gram ofcatalyst, onelbatch being mixed without adding a catalyst. The timerequired for each polymer system to gel is recorded in the table below.

Catalyst; Gel-time, min. None 1440 N-methylmorpholine Dibutyltin oxide 3Dioctyltin oxide 2 The data in this table demonstrates the excellentcatalytic efficiency of representative tin catalysts for modification ofhydroxyl-terminated linear copolymers with aromatic diisocyanates widelyused in the preparation of polyurethanes and further the correlationthereof with the data reported previously.

Example 2 75 grams of a long-chain linear polyester prepared by reactionof adipic acid and diethylene glycol and having a hydroxyl number of50.4 and a carboxyl number of 5.2 were thoroughly mixed with 1.5 ml.water, 2.0 m1. emulsifying agent and 2.0 ml. of a benzene solutioncontaining 50.9% dioctyltin oxide as a catalyst. 25 grams ofmeta-xylylene diisocyanate were then added with vigorous stirring. Themixture was transferred to an open mold as soon as it started foaming.

The foam was removable from the mold about ten minutes after completionof the foaming process, indicating a highly efiicient curing reaction.The foam had a density of 2.97 lbs/cu. it. and compression loads of 0.22and 0.45 psi. at 10 and 50% deflection, respectively.

This example is of particular interest in demonstrating theeffectiveness of tin catalysts in producing polyurethane foams with adiisocyanate that is essentially aliphatic in its characteristics andhitherto incapable of forming foamed polyurethanes with tertiary aminecatalysts.

- Example 3 1250 grams of epsilon-caprolactone, 1268 grams of ethyleneoxide and 67 grams of trimethylolpropane were copolymer-ized at 60 to 70C. in the course of 5.5 hours and in the presence of boron trifiuorideethyl etherate (47% BF to form a branched chain structure having seriesof divalent ethylene and pentamethylene groups connected to one anotherby means of oxy and carbooxy links. The copolymer had a hydroxyl numberof 36.8 and a carboxyl number of 1.3.

75 grams of the copolymer, 1 ml. of emulsifying agent, 2 ml. of Waterand 2 ml. of a benzene solution containing 50.9% dioctyltin oxide werethoroughly mixed. '22 grams of metaxylylene diisocyanate were then addedwith The mixture was transferred to an open mold as soon as it startedfoaming.

As in Example 2, the foam could be removed from the mold about tenminutes after the foaming process was completed, indicating the veryefficient curing reaction.

9. The foam density was 2.24 lbs/ctr. ft. and the foam hadcompressionloads. of 0.13'and 0.26 p.s.i. at 10 and'-50% deflection,respectively.

Example 4 1100 grams. of epsilon-caprolactone, 1100. grams of ethyleneoxide and 62' grams of ethylene glycol werecopolymerized at 65" C1 inthe course of five hours in the presence of 2.6 grams boron trifluorideethyl et-herate (47% BF The resulting linear copolymer had a. hydroxylnumber of 49.1 and a carboxyl number of 1.6.

100 grams of the linear polymer thus prepared were mixed thoroughly with219 grams water and 1.0 ml. dibutyltin. diacetate. 40 grams of a 65.235mixture; of 2,4- and 2,6-tolyl'ene diisocyanatecontaining 0.5% Ethocell,an ethoxylated cellulose, were then added with vigorous stirring. Themixture. was transferred to an open mold'as soon as itstarted foaming.

The foam was removable from the mold about ten minutes after completionof'the foaming, indicating a very efficient curing reaction. The foam;had a density of 2.36 lbs/cu. ft. and compression loads of; 1.15 and1.75 psi. at 1'0 and 50% deflection, respectively.

Example 5 100 grams of the linear copolymer prepared as doscribed in thefirst paragraph of Example-4 were thoroughly mixed with 3.1 ml. waterand 210ml. of 'abenzene solution containing 50.9% dioctyltin' oxide; 40grams of a 65:35 mixture of 2,4- and 2,6-tolylenediisocyanate containing1.0% Ethocell were then-added while stirring vigorously; The mixture wastransferred to an open mold'as soon as'it'started foaming and wasagainremovable from the mold ten minutes afterth'efoaming process wascompieted;

The foam had aremarkably low density of 1.7 4' lbs./ cu.

50% deflection, respectively.

Example 100 grams of the adipic acid-diethylene glycol polyesterdescribedin. Example 2, twov gramsof emulsifying agent, 2.9 ml; waterand 1.0 mldibutyltin. diacetate were thoroughly mixed. 40 grams of a 65235- mixture of 2,4-

and 2,.6-tol.ylene diisocyanate containing 0.5% Ethocell were then.added with vigorous. stirring; The mixture was transferred to an openmold as soon as it started foaming and could be removed from the. moldabout ten minutes after the foaming processwascomplete. Thefoam hadadensity of 2.60 lbs/cu. ft. and compression. loads were 1.07 and 1.10p.s.i. at and 50% deflection, respectively.

Example- 7' 100 grams of a polyester prepared fromv adipicacid and1,2,6-hexanetriol and havinga hydroxyl number of 285 andacarboxylnumberof 0.33. were mixed vigorousl ywith- 72 grams of'a -80:'20mixture of 2,4- and .2,6- to-lylene diisocyanat'e, 2.5 grams ofwater, 0.5 granrof a-n-emulsifying agent (Emulphor EL-719; an ethyleneoxide adduct-of vegetable. oil) and 0.1 gram dibutyltin diluarate. Themixture was transferred to an open mold as soon as it started foamingand was allowed to expand. The foam reached its maxim-um height withinabout ninety seconds and was cured to a rigid foam within about fiveminutes. The foam had a density of 3.4 lbs./ cu. ft.

Example 8' A prepolymer was prepared'by heating 1935 grams polypropyleneglycol 2025 having a hydroxyl number of 58.5, a carboxyl number.of"0.15and a water content of 0.1% with 2 grams of a 80:20 mixtureof 2,4- and2,6-tolylenediisocyanate to 120 C. for three hours. After-this time, 580grams of. additional tolylene diisocyanate were added and the mixturewas held at a temperature of. 100 C. for an. additional hour. Theresulting prepolymer was allowed to cool to room temperature;

208 grams of the prepolymer thus prepared were mixed vigorously with 3.0grams 1,2,6-hexanetriol, 4.1 grams water, 12.1 grams.DC.200 silicone oilhaving a viscosity 0f 50 centistokesand 0.6 gram dibutyltin diacetate.The resulting foam, identified in the table below as Foam A, cured atroom temperature within about thirty minutes.

Thefoaming of the same prepolymer wasrepeated in the same mannerexceptthat 0.6. gram dibutyltin dilaurate was used ascatalyst- The resulting:foam, identified as Foam B, also cured. within about thirty minutes; atroom temperature; The foams hadthe following physical properties:

Foam Foam A B Density, lbs/cu. ft. 2.41 2.85 Tensile-strength, p.s.i. 1618 Compression load at. 25% deflection,

. p.s.i 0.306 0.503 Compression load at 50% deflection,

p.s.i 0.433 0796 Example 9 300 grams polypropylene glycol 2025, having ahydroxyl number of 58.5 and a carboxyl number of 0.15, 4.5 gramsethanol'amine and 0135 gram dibutyltin. dilaurate were mixed at roomtemperature. 51.6 grams of a :35 mixture of 2,4- and 2,6-tolylene;diisocyanate were then added to. and mixed with the initial mixture. Theresulting paste was transferred to a shallow dish and baked for-fourhous at C. The resulting product could be easily handled on a coldtwo-roll rubber mill and the mil-led sheet was a tough elastomer.

Example 10 A prepolymer was prepared'by heating a mixture of 400 gramscastor oil having a hydroxyl number of 161.5, 200 grams of an :20mixture of 2,4- and 2,6 tolylene diisocyanate and 200 grams anhydroustoluene to C. for 1.5 hours. The resulting prepolymer solution had afree isocyanate content*of5;25% NCO.

60 grams of the prepolymer solution thus prepared were mixed with 0.5gram ethylene glycol and 0.023 gram dioctyltin oxide. The mixture wasspread on a glass plate to form afil-m Whichwas allowed to air-dry.After three; days the film was found to possess a. tensile strength of3100 p.s.i. and an elongation of 89.4%. It was found to be essentiallynon-yellowing and to have superior adhesion and improved light stabilitycompared with a similar castoroil-tolylene diisocyana-te film wherein N-methyldiethanolamine was used as the catalyst.

The terms isocyanate and isothiocyanates are used herein to refer tomonoand polyisocyanates and to monoand po-lyisothiocyanates,respectively, including particularly diisocyanates anddiisothiocyanates. While the invention has been described specificallywith reference to the reaction of certain monoisocyanates, diisocyanatesand monoisothiocyanates, it is generically applicable to the reaction ofany compound containing one or more N=C=Y groups in which Y' is oxygenor sulfur. Compounds within this generic definition includemonoisocyanates and monoisothiocyanates of the general formula RNCY inwhich R is a hydrocarbon or substituted hydrocarbon radical such asalkyl, cycloalkyl, alkenyl, alkynyl', aralkyl, aryl, alkaryl, or asubstituted analogue thereof. Examples of such compounds includemethylisocyanate, ethyl isocyanate, butyl isocyanate, .octyl isocyanate,octadecyl isocyanate, vinyl isocyanatc, isopropenyl isocyanate, ethynylisocyanate, benzyl isocyanate, phenyl isocyanate, vinylphenylisocyanate, tolyl isocyanate, ethyl isothiocyanate and phenylisothiocyanate. Also included are 11 polyisocyanatcs andpolyisothiocyanates of the general formula in which at is two or moreand R can be alkylene, substituted alkylene, arylene, substitutedarylene, a hydrocarbon or'substituted hydrocarbon containing one or morearyl-NCY bonds and one or more alkyl-NCY bonds, a hydrocarbon orsubstituted hydrocarbon containing a plurality of either aryl-NCY oralkyl-NCY bonds. R can also include radicals such as -RZR where Z may beany divalent moiety such as -O, ORO-, -CO-, --CO -S--, --SRS, SO etc.Examples of such compounds include hexamethylene diisocyanate,1,8-diisocyanato-p-menthane, xylylene diisocyanates, (OCNCH CH CH OCHl-methyl2,4diisocyanatocyclohexane, phenylene diisocyanates, toly-lenedi isocyanates, chlorophenylene diisocyanates,diphenylmethane-4,4'-diisocyanate, naphthalene-1,S-diisocyanate,tripl1enyl-rnethane-4,4,4"-triisocyanate,xylylene-a,ot-diisothiocyanate, and isopropylbenzene-ctA-diisocyanate.

Further included are dimers and .trirners of isocyahates anddiisocyanates and polymeric diisocyanates of the general formulae nNcYand rntncw i in which x and y are two or more, as Well as compounds ofthe general formula in which x is one or more and M is a monofunctionalor polyfunctional atom or group. Examples of this type includeethylphosphonic diisocyanate, C H P(O) (NCO) phenylphosphonousdiisocyanate, C H P(NCO) compounds containing a ESl-NCY group,isocy-anates derived from sulfonamides (RSO NCO), cyanic acid,thiocyanic acid, and compounds containing a metal-NCY group such astributyltin isocyanate.

It is also to be understood that the active hydrogencontaining compoundsthat are capable of reacting with isocyanates in accordance with themethod of the invention are by no means limited to compounds containinghydroxyl and amino groups but generically include all compounds whichgive a positive test for reactive hydrogen as determined by theZerewitinoif method. Typical of the active hydrogen-containing compoundswhose reaction with isocyanates and isothiocyanates may beacceleratedand in some instances even made possible are compounds containing anoxygen-hydrogen bond, such as water, hydrogen peroxide, alcohols,hydroperoxides, phenols, boronic acids, carboxylic acids, percarboxylicacids and sulfonic acids; compounds containing a nitrogenhydrogen bond,such as ammonia, amines, amides, lactams, ureas, urethanes,allophanates, biurets, acyl ureas, thioureas, hydrazines, oximes,amidines, hydroxylamines, hydrazones, hydroxamic acids, nitramines,diazoamino compounds, and sulfonamides; compounds containing asulfur-hydrogen bond, such as mercaptans, thiopheuols and thioacids;halogen acids; compounds containing active methylene groups andcompounds capable of forming enols such as ace-tone, malonic esters,acetoacetic esters, acetylacetone and nitromethane; and miscellaneousactive hydrogen-containing compounds, such as acetylenic compounds anddialkyl phosphonates. Also included among the applicable activehydrogen-containing compounds are compounds containing two or more ofany one or combination of active hydrogen groups already described.Examples include ethylene glycol, diethylene glycol, hexamethyleneglycol, glycerol, 1,2,6-hexanetriol, sorbitol, dextrin, starch,cellulose, polyvinyl alcohol, ethylene-vinyl alcohol copolymers,cellulose acetate, shellac, castor oil, polyesters, alkyd resins,polyvinyl acetals, polyvinyl ketals, polyethers, polyetheresters,polyacrylic acids, ethylene diamine, hexamethylene diamine,ethanolamines, polyesteramides, poly(hexameth lene adipamide),

wool, and proteins. Materials such as glass and metal which have thinfilms of moisture on their surfaces at the time of reaction with anisocyanate or isothiocyanate are also included.

The method of the invention is particularly suitable for reaction oforganic polyisocyanates with high molecular weight polymers having atleast two end groups containing reactive hydrogen. A preferred class ofsuch polymers includes polyoxyalkylene polyols. These are long chainpolyols containing one or more chains of connected oxyalkylene groups.Most desirably, these polyoxyalkylene polyols are liquids having anaverage molecular weight in the range of 500 to 5000.

Examples of these polyoxyalkylene polyols include polypropylene glycolshaving average molecular weights of 500 to 500, and reaction products ofpropylene oxide with linear diols and higher polyols, said higherpolyols when employed as reactants giving rise to branchedpolyoxyalicylene polyols; and ethylene oxide-propylene oxide hetericcopolyrners having average molecular weights of 500 to 5000 and in whichthe weight ratio of ethylene oxide to propylene oxide ranges between10:90 and 10, including reaction products of mixtures of ethylene oxideand propylene oxide in the said ratios with linear diols and higherpolyols.

Examples of linear diols referred to as reactants with one or morealkylene oxides include ethylene glycol, propylene glycol,2-ethylhexanediol-l,3 and examples of higher polyols include glycerol,trimethylolpropane, 1,2,6- hexanetriol, pentaerythritol and sorbitol.

Another class of polyoxyalkylene polyols are the socalled blockcopolymers having a continuous chain of one type of oxyalkylene linkageconnected to blocks of another type of oxyalkylene linkage. Examples ofsuch block copolymers are reaction products of polypropylene glycolshaving average molecular weights of 500 to 5000 with an amount ofethylene oxide equal to 5 to 25% by weight of the starting polypropyleneglycol. Another class of such block copolymers is represented by thecorresponding reaction products of propylene oxide with polyethyleneglycols.

Further examples of the class of polyoxyalkylene polyols includepolyethylene glycols, polybutylene glycols and copolymers, such aspolyoxyethyleneoxybutylene glycols and polyoxypropyleneoxybutyleneglycols. Included in the term polybutyleue glycols are polymers of 1,2-butylene oxide, 2,3-butylene oxide and 1,4-butylene oxide.

Among the polyesters which are suitable reactants for isocyanates arethose having reactive hydrogen-containing terminal groups, preferablypredominantly hydroxyl groups. Polyesters are reaction products ofpolyols, such as the aforementioned aliphatic polyols and in particularthe class of aliphatic polyols containing from two to ten carbon atoms,with polycarboxylic acids'having from two to thirty-six carbon atoms,e.g., oxalic acid, succinic acid, maleic acid, adipic acid, sebacicacid, isosebacic acids, phthalic acids, and dimer acids such as thoseobtained by coupling two molecules of linoleic acid.

Another preferred class of polymers having terminal groups that containreactive hydrogen atoms and are suitable for reaction withpolyisocyanates are the lactone polymers, preferably those havingmolecular weights within the range of about 500 to 10,000. These includepolymers formed by reaction of polyfunctional initiators having reactivehydrogen atoms with one or more lactones, whereby the lactone rings aresuccessively opened and added to one another as lactone residues to formlong chains, as well as copolymers in which there are random or ordereddistributions of opened lactone residues and alkylene oxides in thechain, and block copolymers thereof. The lactones that are particularlysuitable in polymers and copolymers of this type are theepsilon-caprolactones preferably the unsubstituted caprolactones andcap. rolactones having up to about three alkyl substituents on the ring.The lactone residues and block copolymers may be linked by oxyalkylenechains derived from ethylene oxide, propylene oxide, butylene oxide orthe like, and by polyoxyalkylene chains, e.g., polyoxypropylene,polyoxyethylene, polyoxybutylene chains or mixtures or copolymersthereof.

It is also to be understood that a compound containing reactive NCYgroups and reactive hydrogen, such as a prepolyrneric reaction productof any of the foregoing polymers with an isocyanate, can be reacted withitself or with a compound containing reactive hydrogen, such as water, apolyol or an aminoalcohol.

It is to be expected that numerous modifications will readily becomeapparent to those skilled in the art upon reading this description. Allsuch modifications are intended to be included within the scope of theinvention as defined in the appended claims.

This application is a division of copending application 686,031, filedSeptember 25, 1957, in the name of Fritz Hostettler and Eugene F. Cox.

What is claimed is:

l. The method which comprises reacting castor oil with an organicpolyisocyanate in the presence of a catalytic amount of organotincompound having at least one carbon to tin bond, any remaining bondsfrom tin being to a member of the group consisting of halogen, hydrogen,oxygen, sulfur, nitrogen, and phosphorus atoms. 2. The method whichcomprises forming a film of a mixture of inert vehicle, castoroil-organic diisocyanate prepolymer having unreacted isocyanato groupsand produced by reacting a molar excess of organic diisocyanate withcastor oil, alkylene glycol, and a catalytic amount of organotincompound having at least one carbon to tin bond, any remaining bondsfrom tin being to a member of the group consisting of halogen, hydrogen,oxygen, sulfur, nitrogen, and phosphorus atoms; and subsequentlyremoving said inert vehicle from said film and reacting said prepolymerwith said alkylene glycol to form an essentially non-yellowing, tough,adherent coating.

References Cited in the file of this patent UNITED STATES PATENTS Evanset al July 7, 1959

1. THE METHOD WHICH COMPRISES REACTING CASTOR OIL WITH AN ORGANICPOLYISOCYANATE IN THE PRESENCE OF A CATALYSTIC AMOUNT OF ORGANOTINCOMPOUND HAVING AT LEAST ONE CARBON TO TIN BOND, ANY REMAINING BONDSFROM TIN BEING TO A MEMBER OF THE GROUP CONSISTING OF HALOGEN, HYDROGEN,OXYGEN, SULFUR, NITROGEN, AND PHOSPHORUS ATOMS.